I am using a DRO glass encoder for gecko 320

[rokag3]

I am using a glass encoder 5 micron to drive my 320 gecko.
It work fine on the kitchen table but now the question is how to send the signal back to my DRO ?
I use the sn75176A differential bus transceiver i have A,B and NOT A, NOT B.
I use AB line for the gecko and will use notAnotBfor the DRO
I want to use the power suply of the DRO for the encoder
I will have to put a 470 ohms to the term6 and term7 on the gecko
question:
I will have to connect the ground of my encoders DRO to the gecko encoder- do this mean that the ground of my gecko will be linked to the ground of the DRO?
if so what is the danger ?
I presume that the external(DRO) 5V should not be connected to encoder+
corect?

[Al_The_Man]

Essentially it looks like you have it correct.
The 5v supply commons of each will have to be connected together.
The DRO supply common may be at Earth Ground potential, this may or may not be a problem, depending on what method of grounding or isolation you are seeking.
The +5v should not be connected together.
Depending on the internal condition of the drive input, you may not need a pull up with the 75176?
Al.

[rokag3]

I am not very confident to link my friends DRO with the notorious fluctuating ground of the 320 when used with more than 4A servo in my case 8.8A 72V

Mariss address the problems but i never could find the circuit he posted !

servos motor gecko DRO encoder?

Also is it good practice to use another 2 opto on the same line one already in the gecko and another one to isolate the ground?

[Al_The_Man]

If you are concerned about establishing Earth ground isolation, check the 5v supply common of the DRO and see if it is referenced to Earth Ground or not.
If it is not, there should be nothing to worry about.
I reference all my systems to a common point Earth Ground anyway.
Al.

[rokag3]

ok i will check that

[rokag3]

hello,
the linear encoder of the DRO is connected to the ground!
so my gecko is also connected to the ground so crossfinger and go